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Patented May 27, 1941 UM D ras tries STABLE DRY OXEDIZIN G MIXTUREHAVING CONTROLLED OXYGEN EVOLUTION RATE WHEN USED IN SOLUTION Joseph L.Richmond, Woodstown, N. .12, assignor to E. I. du Pont de Nemours &Company, Wilmington, DeL, a. corporation of Delaware No Drawing.Application June 16, 1939, Serial No. 279,391

4 Claims.

This invention relates to a stable oxidizing mixture having aregulated'rate of oxygen evolution. More particularly it relates to adry mixture comprising a per-salt as the principal ingredient togetherwith a wetting agent, a stabilizing agent and an oxygen evolution accelcrating agent. p

This case is a continuation-in-part of applicants copending applicationSerial No. 229,675, filed September 13, 1938.

Many oxidizing materials are known, but nearly all of them have distinctdisadvantages. One

of the most serious disadvantages of such materials is a tendency todeteriorate upon standing.

This tendency is present, for example, in hydrogen peroxide and insodium perborate, two well known oxidizing agents. Another disadvantageis that stabilized oxidizing materials will not evolve their oxygen at arate which is satisfactory in textile operations and likewise will notevolve all the active oxygen contained in the product, thereby cuttingdown the effective strength of the agent. The textile industry, inparticular, evidences a need for an oxidizing agent for vat dyestuffswhich agent will not deteriorate upon standing; which is stable to ironso that it can be used in iron equipment and which evolves all of itsoxygen at the optimum rate for textile operations.

This invention has as an object the preparation of an improved oxidizingagent. Another object is the provision of a stable, solid oxidizingmaterial for use in the textile industry. A

specific examples wherein the parts stated are by weight.

Example 1 Five hundred fifty six parts of sodium perborate monohydrate,37 parts of sodium pyrophosphate, 333 parts of anhydrous sodium sulfateand '14 parts of the sodium salts of a mixture of coconut oil fattyalcohol sulfates are intimately mixed in a suitable apparatus. A drystable product containing 8.5% available oxygen is obtained.

Example 2 Eight hundred fifty six parts of sodium perboratetetrahydrate, 37 par-ts of sodium pyrophosphate,.-33 parts of anhydroussodium sulfate and 74 parts of the sodium salts of a mixfurther objectis to provide an improved oxidiz- I ing agent wherein sodium perborateis the principal ingredient. Another object is the preparation of a.stable oxidizing agent which will devention are compounded bymixing thefinely divided. ingredients together in the dry solid state until'anintimate mixture is obtained, any

suitable mixing apparatus being used.

' The invention is illustrated by the following ture of coconut oilfatty alcohol sulfates are intimately mixed in a suitable apparatus. Adry stable product containing about 8.5% available oxygen is obtained.

In order to test the oxidizing effect of the compositions made inExamples 1 and 2 the following procedure was carried out. A solution ofeach of the above two mixtures was prepared containing 0.026% availableoxygen. The solutions were heated at F. The loss of available oxygen wasdetermined at regular intervals by withdrawing aliquot portions andtitrating the residual avail-able oxygen with standard potassiumpermanganate solution. The results are contained in the following table:

Table I Percent of available oxygen liberated Time, minutes Example 1Example 2 Asm-ay be readily seen from the above table, with the otherthree ingredients held constant, an'increa'se in the percentage ofanhydrous so-f dium sulfate in the dry mix results in an increase in therate of oxygen evolution from sition in solution. I i I The oxidizingeffect of the products of the above examples was also tested on dyeingsof vat dyestuffs and the said products were found to be superior tosodium per-borate, weight for weight.

In order to more fully illustrate the effect of the compovariation ofthe composition, the following examples are set forth in tabular form:

laarts of sogarts of so- Parts of Parts of rum permm pyroso rum Exampleborate monophosphate sulfate ang 'gzt hydrate anhydrous hydrous gWetting agent" in the above examples signifies the sodium salts of amixture of coconut oil fatty alcohol sulfates.

The rate of liberation of available oxygen from the mixtures of ExamplesIII to XIII tested as above described are set forth in Tables HA andIIB.

Table IIA Percent of available oxygen liberated Time, minutes Ex. Ex.Ex. Ex Ex. Ex.

III IV V VI VII VIII Table IIA clearly shows that the invention may bepracticed with wide variations in the composition in the mixture withresulting variations in the rate of oxygen liberation. Since varioususes of the oxidized compositions will require different rates of oxygenevolution in order to maintain maximum efficiencies in the variousoperations involved, it is highly important that the rate of evolutionof oxygen be adjustable to take care of the particular situation. Thisflexibility is considered one of the most important features in thepresent invention.

Table IIB Percent of available oxygen liberated 'Iirne, minutes Ex. Ex.Ex. Ex. Ex.

IX X XI XII XIII The results in Table IIB show a number of importantfacts. It is known that sodium perborate deteriorates on standing andsodium pyrophosphate is added to stabilize the sodium perborate. Acomparison of the rate of liberation of oxygen in Example IX and ExampleX shows that sodium pyrophosphate not only stabilizes the dry sodiumperborate but also materially retards oxygen Among the per-saltssuitablefor the mixtures of the present invention, there may bementioned by way of example, sodium percarbonate sodium perphosphate,sodium or ammonium persulfate, etc. The preferred per-salt is sodiumperborate, which may be used as either the monohydrate or as thetetrahydrate, the water of crystallization being inert in the mixture.Suitable adjustment of parts must be made if the tetrahydrate is usedinstead of themonohydrate to provide the same percentage of availableoxygen in the mixture.

The preferred stabilizing agent is sodium pyrophosphate. The preferredoxygen-evolution-accelerating agent is sodium sulfate.

Sec.-pentadecy1 sodium sulfate, cetyl betalne, alkylated naphthalenesulfonate, paraffin sulfonic acid and Turkey red oil are mentioned asexamples of wetting agents which may be used in the novel mixture. Thepreferred wetting agents, however, are the salts of higher aliphaticalcohol sulfates having 8 to 18 carbon atoms in the alkylradical. Asexamples of such compounds, mention is made of secondary-hexadecyl,secondary-heptadecyl and secondary-pentadecyl sodium or ammoniumsulfates, sodium oleyl sulfate, pentadecyl-B-sodium sulfate, etc. Thewetting agent ingredient of the novel mixture may be one of the wettingagents used alone or in mixture of one with another or others.Especially preferred as the wetting agent ingredient is sodium lorolsulfate. This is a mixture of the sodium salts of coconut oil fattyalcohol sulfates made by catalytically hydrogenating coconut oil toproduce the corresponding alcohols -(known tothe trade as Lorol) andsulfating by known methods. Lorol is a mixture of saturated fattyalcohols of from ten to eighteen carbon atoms. The mixture containsabout fifty percent of dodecyl alcohol.

The novel oxidizing mixture of the invention must have the oxidizingagent as the principal ingredient. Using the preferred ingredients asexamples, the preferred proportions of ingredients are sodium perboratecalculated as the monohydrate (NaBOaHzO) in the amount of 40% to sodiumlorol sulfate in the amount of 5% to 10%, sodium pyrophosphate in anamount of 3% to 40% and sodium sulfate in an amount of 0.37% to 40%.

Although no theoretical explanation is known to the applicant, accordingto the present invention, the addition of small amounts of a wettinagent, a stabilizing agent and an oxygen-evolution-accelerating agent toa per-salt produces an oxidizing mixture superior to its chemical effecton vat dyeings and superior in itskeeping qualities over the per-saltalone. Not only are such mixtures free of deterioration on standing, but

also they are not sensitive to iron, and, hence can be uSed in the ironequipment usually employed in oxidizing vat colors. By using the properproportions of stabilizing agent and the oxygen-evolution-acceleratingagent, the rate and extent of evolution of oxygen from the persalt isadjusted so that when used in a textile operation, maximum efficiency isobtained.

It has been found desirable to so regulate the oxidizing mixture that itcontains about 8.5% available oxygen and this is a preferred embodimentof the invention.

While for the purpose of treating fabrics in dyeing processes it isdesirable to have a wetting agent present to assist in bringing thesolution made from the oxidizing mixture into contac am ss with thefabric, the wetting agent is not believed to materially affect therateof oxygen evolution, and, hence, it may be omitted from the mixturewhere this function is unnecessary;

The stabilizer is of primary importance in improving the keepingqualities of the dry mixture. Where there is no storage periodcontemplated and where an oxidizing agent having a high rate of oxygenliberation is desired the stabilizer may be omitted. A mixture ofper-salt and sodium sulfate gives a higher rate of oxygen liberationthan is obtained by the per-salt alone, and this is a feature of thepresent invention. Under these circumstances the ingredients may bemixed directly in solution.

This invention has the advantage that the oxidizing composition isstable, thus reducing need for rapid turnover. Its oxygen-evolution-rateis controlled, assuring a substantially constant oxidizing power. It maybe used without testing for strength and changing of formulae from dayto day. The composition is a dry solid, soluble in water, permittingeasy handling and weighing. The stability of the mixture to iron permitsits use in iron equipment and also the presence of iron impurities inthe ingredients. Being a dry mechanical mixture, the new oxidizingcomposition is'easily and cheaply prepared.

It is to be understood that the invention is not limited to the specificembodiments herein described, the proper limits being defined by thescope of the appended claims.

I claim:

1. An oxidizing composition, which is a mixture of dry materials,comprising sodium perborate as the principal ingredient, a wettingagent, sodium pyrophosphate as a stabilizing agent and normal sodiumsulfate as an oxygenevolution-accelerating agent.

2. An oxidizing composition, which is a mixture of dry materials,comprising sodium perborate as the principal ingredient, a water solublesalt of a higher aliphatic alcohol sulfate, sodium pyrophosphate as astabilizing agent and normal sodium sulfate as anoxygen-evolutionaccelerating agent.

3. An oxidizing composition having about 8.5% available oxygen, which isa mixture of dry materials, comprising sodium perborate as the principalingredient, a water soluble salt of an alkyl sulfate, the aliwl radicalcontaining 8 to 18 carbon atoms, sodium pyrophosphate and normal sodiumsulfate as an oxygen-evolution-accelerating agent.

4. An oxidizing composition, which is a mixture of dry materials,comprising to sodium perborate, 5% to 10% of the sodium salts of amixture of coconut oil fatty alcohol sulfates, from 3% to 40% sodiumpyrophosphate and from 0.37% to 40% normal sodium sulfate as anoxygen-evolution-accelerating agent.

JOSEPH L. RICHMOND.

